In order for a will to be valid, the person making it must have ‘testamentary capacity’ – the legal term for being ‘of sound mind. Challenges to a will on the ground that the person who made it (the ‘testator’) did not have testamentary capacity – especially where the will was made when the testator was elderly and infirm or suffering from mental illness – are common.

A Scottish case recently considered the validity of a will made by a builder and property developer who died in 2008. He had made a will in 2005 and added two codicils to it in 2008. These left the whole of his estate of nearly £7 million to a charitable trust.

An expert report concluded that there was clear evidence that the testator ‘had an abnormal pattern of interacting with members of his family’ and that ‘it is highly likely at times, his abnormal beliefs reached delusional intensity, tipping him into periods of psychosis during which he lost contact with reality’.

A great deal of evidence as to the man’s mental fitness or lack thereof was produced, with the result that the judge had ‘no difficulty in accepting it was common ground … that the testator had a paranoid personality disorder’.

The judge said that the critical question, therefore, was whether that disorder was ‘at times of such intensity that it affected the testator’s mind in such a way as to deprive him of testamentary capacity’. If the answer to that question was yes, the further question would then arise as to whether that had occurred at the times when the will and the two codicils were signed.
 
In the event, the court was not satisfied that the family had ‘established that there were periods when the testator’s paranoid personality disorder was of such delusional intensity as to deprive him of testamentary capacity’.

Accordingly, the will was deemed to be valid.